Most cat litter is made from clay (e.g., bentonite) that acts as an absorbent. Since clay typically contains elevated levels of naturally-occurring radionuclides, large amounts of cat litter can be measurably radioactive. Shipments of cat litter have been known to trip radiation monitors.

I would not be placing any cat litter of any kind in or near my garden.

Power Conserver

I dont want to add clay to my soil, strange as that my sound. What I want to add is mycelium.
I have been studying soil restoration after trying and failing to do this for the last few years. I decided I needed to actually learn how to do this rather than just think its a good thing to do.
What I learned is that we need to add more carbon to the soil- twigs, dried leaves,cut up branches, along with the green leftovers.
After years of adding organic matter in the form of lawn clippings and spent vegie plants, I wasnt seeing the rise in water retention I was expecting to see.
I stopped making compost in dedicated bins a number of years ago and instead, have been 'chopping and dropping' and importing woodchip from where ever I could.

I bought a bag of NZ Oyster mushrooms so I could watch how they grew and learn from them. To be honest, they have a different texture to supermarket mushrooms, a lot more chewy and I'm not too keen on that, but, I decided that I needed to educate my taste buds....so I bought another bag of a slightly different strain from the same source and am currently growing that one up to the point where it will produce mushrooms.

When the first bag mushrooms started to put out spores....because of the extreme temperature variations, I decided to experiment with it, so I gathered up soil and mulch from all around my back yard, used that to fill up a pyrex jug, added a couple of bags of sterilized wood dowels and popped the contents of the bought bag on top. This sits on a bookcase in my hall where it is not in direct sunlight.
It gets misted with rainwater often throughout the day and sometimes I take the jug into a better lit spot so I can look at what is happening.

The dowels will be fished out at some point in the near future and put in holes in trunks of my cut branches of my NZ Cabbage tree. These trunks will then be set on a block off the ground in a very shady part of my yard to do there thing. At some point, I expect that they will have real home grown mushrooms growing out of the trunk. If not, then its back to the drawing board.
What I will do with the original content, hoping that it still has active mycelium, is plant it outside in an area that is well shaded and with other native plants and trees, just to see what will happen- will it continue to grow and spread?

I've finished reading Paul Stamets book, 'Mycelium Running' and am current working my way though Michael Phillips on 'Mycorrhizal Planet'.
I feel like I have found the missing link.

Another experiment I have been doing after what I have read so far, is to put little pieces of innoculated wood in the ground beside each of my sweet corn seedlings. This is a different type of mushroom- the Burgandy mushroom. Its supposed to love growing in soil that has a high organic matter content.

And yet another, is adding a small piece of active mycelium to my vegetable seedlings. One in the smallest honeynut butternut, so I could see how this grew compared to those that havent been inoculated.

Sustainability Master

I have been reading a lot about mycelium helping plants lately. I was thinking of growing King Stropharia (I believe the same as what you called burgundy mushroom) in the shadier parts of my garden; I can use hay to get them started. My biggest problem with growing mushrooms is that the vast majority of them want hardwood- as chips or for plugs- and we simply don't have them in our area; it's all pine and juniper. There is a variety of oyster mushroom that grows on softwood, which I may try. We also have morels, but they seem to be very difficult to domesticate.

Super Self-Sufficient

I think you are on the right track, adding organic matter to your soil. Everything that I've read says that adding clay is counterproductive. Clay + sand + water = cement. You might look into ordering some wine cap mushroom spawn. I bought some about 3 years ago, and they have naturalized here and there in my orchard and garden. They can be grown on wood chips, sawdust or straw.

Super Self-Sufficient

I have been reading a lot about mycelium helping plants lately. I was thinking of growing King Stropharia (I believe the same as what you called burgundy mushroom) in the shadier parts of my garden; I can use hay to get them started. My biggest problem with growing mushrooms is that the vast majority of them want hardwood- as chips or for plugs- and we simply don't have them in our area; it's all pine and juniper. There is a variety of oyster mushroom that grows on softwood, which I may try. We also have morels, but they seem to be very difficult to domesticate.

I just did a post about that variety of mushroom. They have naturalized here and there on wood chips in my orchard and garden. Can you contact a local wood worker to get some wood chips or sawdust? You wouldn't need very much to create a patch. About 2 - 4" deep, perhaps an area 3 x 6' would give you a great bed. You could then mulch it with oak or other hardwood leaves.